	function drawRoundRectPath(cxt, width, height, radius) {
		cxt.beginPath(0);
		//从右下角顺时针绘制，弧度从0到1/2PI  
		cxt.arc(width - radius, height - radius, radius, 0, Math.PI / 2);

		//矩形下边线  
		cxt.lineTo(radius, height);

		//左下角圆弧，弧度从1/2PI到PI  
		cxt.arc(radius, height - radius, radius, Math.PI / 2, Math.PI);

		//矩形左边线  
		cxt.lineTo(0, radius);

		//左上角圆弧，弧度从PI到3/2PI  
		cxt.arc(radius, radius, radius, Math.PI, Math.PI * 3 / 2);

		//上边线  
		cxt.lineTo(width - radius, 0);

		//右上角圆弧  
		cxt.arc(width - radius, radius, radius, Math.PI * 3 / 2, Math.PI * 2);

		//右边线  
		cxt.lineTo(width, height - radius);
		cxt.closePath();
	}
/**该方法用来绘制一个有填充色的圆角矩形 
     *@param cxt:canvas的上下文环境 
     *@param x:左上角x轴坐标 
     *@param y:左上角y轴坐标 
     *@param width:矩形的宽度 
     *@param height:矩形的高度 
     *@param radius:圆的半径 
     *@param fillColor:填充颜色 
     **/
    export const fillRoundRect = (cxt, x, y, width, height, radius, /*optional*/ fillColor) => {
        //圆的直径必然要小于矩形的宽高          
        if (2 * radius > width || 2 * radius > height) { return false; }

        cxt.save();
        cxt.translate(x, y);
        //绘制圆角矩形的各个边  
        drawRoundRectPath(cxt, width, height, radius);
        cxt.fillStyle = fillColor || "#000"; //若是给定了值就用给定的值否则给予默认值  
        cxt.fill();
        cxt.restore();
    }
	
/**该方法用来绘制圆角矩形 
     *@param cxt:canvas的上下文环境 
     *@param x:左上角x轴坐标 
     *@param y:左上角y轴坐标 
     *@param width:矩形的宽度 
     *@param height:矩形的高度 
     *@param radius:圆的半径 
     *@param lineWidth:线条粗细 
     *@param strokeColor:线条颜色 
     **/
    export const  strokeRoundRect = (cxt, x, y, width, height, radius, /*optional*/ lineWidth, /*optional*/ strokeColor) => {
        //圆的直径必然要小于矩形的宽高          
        if (2 * radius > width || 2 * radius > height) { return false; }

        cxt.save();
        cxt.translate(x, y);
        //绘制圆角矩形的各个边  
        drawRoundRectPath(cxt, width, height, radius);
        cxt.lineWidth = lineWidth || 2; //若是给定了值就用给定的值否则给予默认值2  
        cxt.strokeStyle = strokeColor || "#000";
        cxt.stroke();
        cxt.restore();
    }